US 20050075835 A1 Abstract A method and system of real-time statistical bin control. First, a statistical bin control rule is generated by a statistical bin control rule generator, and a test result having an error frequency is then retrieved from test equipment. If the error frequency exceeds a preset limit, the system replies to the test equipment with a first action corresponding to the statistical bin control rule. Next, if the error frequency of the test results exceeds another limit, the system then replies to the test equipment with a second action corresponding to the statistical bin control rule.
Claims(28) 1. A method of real-time statistical bin control for classification of results from test equipment and responding correspondingly, comprising the steps of:
retrieving test results from the test equipment; checking if a number of consistent returns of one result type exceeds a first limit; responding with a first action corresponding to the one result type and a statistical bin control rule if the number of consistent returns exceeds the first limit; checking if a number of accumulative returns of one result type exceeds a second limit; and responding with a second action corresponding to the one result type and the statistical bin control rule if the number of accumulative returns exceeds the second limit. 2. The method as claimed in 3. The method as claimed in 4. The method as claimed in 5. The method as claimed in 6. The method as claimed in 7. The method as claimed in 8. A system of real-time statistical bin control for classification of test results from test equipment and responding with a corresponding action, comprising:
a statistical bin control unit for retrieving the test results having a number of consistent returns from the test equipment, checking if the number of consistent returns of one result type exceeds a first limit, responding with a first action corresponding to the one result type and a statistical bin control rule if the number of consistent returns exceeds the first limit, checking if a number of accumulative returns of one result type exceeds a second limit, and responding with a second action corresponding to the one result type and the statistical bin control rule if the number of accumulative returns exceeds the second limit. 9. The system as claimed in 10. The system as claimed in 11. The system as claimed in 12. The system as claimed in 13. The system as claimed in 14. The system as claimed in 15. A method of real-time statistical bin control for receiving a test result from test equipment and responding to the test equipment with a corresponding action in accordance with the test result, comprising the steps of:
obtaining of CP testing history data from a statistical bin control database by a statistical bin control rule generator; generating a statistical bin control rule according to the CP testing history data; retrieving the test results from the test equipment; checking if a number of consistent returns of one result type exceeds a first limit; responding with a first action corresponding to the one result type and a statistical bin control rule if the number of consistent returns exceeds the first limit; checking if a number of accumulative returns of one result type exceeds a second limit; and responding with a second action corresponding to the one result type and the statistical bin control rule if the number of accumulative returns exceeds the second limit. 16. The method as claimed in 17. The method as claimed in 18. The method as claimed in 19. The method as claimed in 20. The method as claimed in 21. A system of real-time statistical bin control for receiving a test result from test equipment and responding to the test equipment with a corresponding action in accordance with the test result, comprising:
a statistical bin control rule generator for generating a statistical bin control rule in accordance with CP testing history data; and a statistical bin control unit for retrieving the test results having a number of consistent returns from the test equipment, checking if the number of consistent returns of one result type exceeds a first limit, responding with a first action corresponding to the one result type and the statistical bin control rule if the number of consistent returns exceeds the first limit, checking if a number of accumulative returns of one result type exceeds a second limit, and responding with a second action corresponding to the one result type and the statistical bin control rule if the number of accumulative returns exceeds the second limit. 22. The system as claimed in 23. The system as claimed in 24. The system as claimed in 25. The system as claimed in 26. The system as claimed in 27. A storage medium, comprising a program with a plurality of codes for implementing steps of:
retrieving test results from the test equipment; checking if a number of consistent returns of one result type exceeds a first limit; responding with a first action corresponding to the one result type and a statistical bin control rule if the number of consistent returns exceeds the first limit; checking if a number of accumulative returns of one result type exceeds a second limit; and responding with a second action corresponding to the one result type and the statistical bin control rule if the number of accumulative returns exceeds the second limit. 28. A storage medium, comprising a program with a plurality of codes for implementing steps of:
obtaining of CP testing history data from a statistical bin control database by a statistical bin control rule generator; generating a statistical bin control rule according to the CP testing history data; retrieving the test results from the test equipment; checking if a number of consistent returns of one result type exceeds a first limit; checking if a number of accumulative returns of one result type exceeds a second limit; and Description 1. Field of the Invention The present invention relates to a system and method of statistical bin control, and in particular to a system and method of real-time statistical bin control of test equipment and error state recovery thereof in accordance with statistical bin control data. 2. Description of the Related Art In integrated circuit manufacturing, testing is the final step, detecting defects generated during the process and ascertaining causes thereof. Testing enhances yield rate and development of data for manufacturing analysis. Integrated circuit testing can comprise circuit probe (or wafer sort), and final test (or package test). Circuit probe (CP) testing is executed among wafer formations to detect the quality of the dies before the package process for avoiding the wasting of both time and costs. When memory product testing is performed, recoverable dies verified by circuit probe are recovered by laser repair to raise the yield rate. Final testing is performed after the package process to ensure that chips conform to the standards. However, in most situations, abnormal test results can be caused by contamination of probe-needles or other abnormal conditions of the test equipment rather than actual wafer defects, generating a clean needle command by a monitoring system to clean the probe-needles after testing. Although the monitoring system acts on errors in the presence of contamination of the probe-needles or any abnormal condition, in fact, any individual occurrence of contamination or other abnormal condition rarely adversely influences the test results, despite slowing the performance of the test equipment causing reduced capacities. As a result, a statistical control method is required to determine when to clean the probe-needles or act on errors if the number of detected abnormal situations reaches a critical number. Statistical process control (SPC) thus improves the process, maintains the control states, and prevents the production of defective products. Statistical process control can consider manufacturing process events from the past, govern present conditions, and predict effects in the future. In addition, in the conventional method, there is no automation link between the control system and test equipment, such that statistical bin control data must be handled manually with offline statistical control at a predetermined time (for example, a day) in accordance with conditions predetermined by the test results of wafers and system shutdown. The test equipment is forced to stop the testing procedure by the way of suspending the test program when the test results reach the predetermined conditions for system shutdown. However, tested wafers must be re-tested in this period to determine whether their test results are correct. Thus, test equipment wastes considerable time re-testing, and the performance is affected. Therefore, it is an important object to detect abnormal states early and return the test equipment to the normal state of operation. It is therefore an object of the present invention to provide a method and system of real-time statistical bin control to improve processing time and avoid extra costs. To achieve this and other objects, present invention provides a method and system of real-time statistical bin control for collecting error messages from test equipment for statistical classification, and enabling test equipment error state recovery according to the statistical data classification. According to one embodiment of the invention, a method of real-time statistical bin control performs the following steps. First, a statistical bin control rule generator obtains CD testing history data from a statistical bin control database and generates statistical bin control rules accordingly. A test result is retrieved from test equipment and according thereto, the system checks whether a number of consistent returns of one result type exceeds a first limit. The system replies to the test equipment with an action corresponding to the one result type and the statistical bin control rule if the number of consistent returns one result type exceeds the first limit. Next, if a number of accumulative returns of one result type exceed a second limit, the system also replies to the test equipment with an action corresponding to the one result type and the statistical bin control rule if the number of accumulative returns of one result type exceeds the second limit. According to another embodiment of the invention, a system of real-time statistical bin control comprises a statistical bin control rule generator and a statistical bin control unit. The statistical bin control rule generator generates a statistical bin control rule in accordance with CP testing history data, The statistical bin control unit retrieves a test result from the test equipment and according thereto, the system checks whether a number of consistent returns of one result type exceed a first limit. The system replies to the test equipment with an action corresponding to the one result type and the statistical bin control rule if the number of consistent returns one result type exceeds the first limit. The system then checks whether a number of accumulative returns of one result exceed a second limit and if so, replies with a second action corresponding to the one result type and the statistical bin control rule if the number of accumulative returns of one result type exceeds the second limit. A detailed description is given in the following embodiments with reference to the accompanying drawings. The present invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein: The present invention discloses a system of real-time statistical bin control (SBC) for detecting abnormal test results from circuit probe testing and performing a real-time recovery action according to the test result. The SBC rule generator The circuit probe test equipment Test results are stored in the accumulative bin buffer In step S In step S In step In step S In step S In step S In step S In step S In step S In step S In step S In step S In step S In step S In step S In step S In step S In step S In step S In step S In step S In step S In step S In step S The method of real-time SBC according to the invention establishes an automated link between control and test equipment to set various SBC conditions and abnormal states removing commands thereof. The system issues commands without manual operation using the automated link to the test equipment to respond to abnormal conditions or errors, without suspending the testing procedure. While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements. Referenced by
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